There is known a clutch unit for vehicle, hereinafter also referred as vehicle clutch unit, of JP-A-2006-290344.
The vehicle clutch unit has an input-side clutch which includes an inner ring having a cam surface on an outer circumferential surface, an outer ring having a bottomed cylindrical shape, and a roller provided in a wedge-shaped space formed between the inner ring and the outer ring. A torque input to the input-side clutch is transmitted to the inner ring, and the torque transmitted to the inner ring is transmitted to the outer ring through the roller.